首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2264篇
  免费   168篇
  国内免费   19篇
耳鼻咽喉   54篇
儿科学   68篇
妇产科学   101篇
基础医学   183篇
口腔科学   105篇
临床医学   248篇
内科学   523篇
皮肤病学   60篇
神经病学   150篇
特种医学   83篇
外科学   476篇
综合类   32篇
预防医学   104篇
眼科学   55篇
药学   73篇
中国医学   3篇
肿瘤学   133篇
  2023年   28篇
  2022年   22篇
  2021年   33篇
  2020年   43篇
  2019年   57篇
  2018年   71篇
  2017年   65篇
  2016年   89篇
  2015年   97篇
  2014年   120篇
  2013年   158篇
  2012年   167篇
  2011年   180篇
  2010年   97篇
  2009年   109篇
  2008年   136篇
  2007年   193篇
  2006年   157篇
  2005年   156篇
  2004年   112篇
  2003年   83篇
  2002年   72篇
  2001年   40篇
  2000年   42篇
  1999年   30篇
  1998年   10篇
  1997年   11篇
  1996年   10篇
  1995年   3篇
  1994年   2篇
  1993年   2篇
  1992年   4篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   2篇
  1978年   2篇
  1977年   2篇
  1974年   1篇
  1973年   4篇
  1972年   5篇
  1971年   1篇
  1970年   5篇
  1969年   1篇
  1968年   1篇
  1967年   3篇
  1966年   1篇
  1965年   1篇
  1963年   1篇
  1960年   1篇
排序方式: 共有2451条查询结果,搜索用时 0 毫秒
61.
Storage of skin grafts for later use is one of the standard applications in surgery. It is the most preferred method to maintain at +4°C in refrigeration after wrapping the surplus grafts into sterile gauze pad moistened with saline. Although there are many studies on the storage of skin grafts, less is known about storing skin grafts with PRP. Twenty‐five pieces of 1 × 1 cm2 partial thickness skin graft were harvested from 12 patients during the reduction mammoplasty operation. Twenty‐four grafts were divided into 4 groups, and each group consisted of 6 grafts, 1 graft was analyzed as Day 0. Grafts in Group 1, 2, and 3 were wrapped by sterile gauze pad moistened by either saline (Group 1) or Hartman (Group 2) or PRP (Group 3). Grafts were analyzed macroscopically and microscopically. There were no significant differences between media for the first 10 days. Decrease in viability was less in saline and PRP wrapped grafts at 20 day, viability decreased significantly in all environments after 20 days. Although there was no significant difference in saline or PRP storage, it was observed macroscopically that the grafts stored in the PRP appeared better.  相似文献   
62.
This study aims to determine the efficacy of omalizumab, a humanized monoclonal anti‐immunoglobulin E antibody, in patients with chronic spontaneous urticaria (CSU) refractory to conventional therapy, together with the evaluation of serum CRP levels. All the patients with a diagnosis of CSU who were continuously treated with omalizumab (300 mg/mo) for at least 3 months between June 2016 and July 2019 were included in this study. Urticaria activity score (UAS‐7) was used for assessment of disease activity. Serum CRP levels were also retrospectively analyzed. When UAS‐7 scores before the initiation of therapy were compared to the week 4, 12, 24, and 36 scores after the treatment, each were significantly different from the pretreatment results (P < .01). CRP level prior to treatment was found to be strongly correlated with baseline UAS scores of the patients' (P = .00). At the 12th week of treatment, decline of CRP level was positively and strongly correlated with the decline of UAS (P = .037). In this study, mean UAS decreased, mean rescue medication use declined, and overall therapeutic response improved with omalizumab treatment. Additionally, significant correlation between the decline of CRP levels and treatment response was found.  相似文献   
63.
64.
This experimental study was designed to assess and to compare intra-abdominal adhesions following the use of five commercially available prosthetic mesh grafts in the repair if abdominal wall defects. Sixty Wistar albino rats were randomly divided into six groups (n = 10). A 2 × 1 cm defect at abdominal wall was created and defects were closed either primarily or with one of the following prosthetic mesh grafts: monofilament polypropylene, polytetrafluoroethylene, sodium hyaluronate/carboxymethylcellulose-coated polypropylene, polypropylene/polyglactin 910 composite, or resorbable hydrophilic collagen-coated multifiber polyester. The severity of adhesions was graded, tensile strengths of adhesions were measured, and histopathological grades of inflammation and fibrosis were evaluated. Polypropylene mesh resulted in more adhesion formation in comparison to primary repair and other grafts used in this study, except polypropylene/polyglactin 910 composite mesh. In addition, the highest tensile strength of omental adhesions was detected in the polypropylene group (χ2 = 26.249; p =. 0001). Polyester composite mesh caused the least adhesion formation among the groups. Sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polyester composite meshes revealed the highest fibrosis scores (χ2 = 50.776; p =. 0001). The highest inflammatory activity was detected in the polytetrafluoroethylene mesh group (χ2 = 16.564; p =. 005). Thus, sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polytetrafluoroethylene meshes following polyester composite mesh were the minimal adhesion-forming grafts in this study. Disadvantages of the polytetrafluoroethylene mesh were lower fibrotic activity and higher inflammatory reaction to the graft.  相似文献   
65.
Unknown impurities were detected in simvastatin substance and tablets at a 0.2% level using the liquid chromatography technique with UV (DAD) detection. The impurity structures were elucidated by a direct hyphenation of liquid chromatograph to high-resolution mass spectrometer with electrospray ionisation interface using solutions of formic acid in water and in acetonitrile as the mobile phase. Peak tracking was performed using the column-switching technique. Accurate mass measurements by quadrupole time-of-flight mass spectrometer equipped with lock-spray provided information about elemental composition of intact molecules and fragments of impurities. Measurement accuracy for precursor ions was around 3 ppm and for fragment ions between 4 and 13 ppm. Mass resolving power was around 6500. Deduced molecular formulae for A1, A2 and A3 impurities were C(27)H(44)O(6), C(26)H(43)O(6) and C(26)H(41)O(5), respectively. The structures proposed for all three impurities revealed modifications of simvastatin molecule on the lactone ring. Impurity A1, detected in simvastatin tablets, was identified as ethyl ester, while the impurities A2 and A3, detected in simvastatin substance, were identified as methyl ester and methyl ether of simvastatin. The impurity from tablets was synthesized and its structure confirmed by LC-UV, LC-MS/MS, and NMR techniques.  相似文献   
66.
A speciation procedure for chromium(III) and chromium(VI) in the water and food samples has been established in the presented work. The procedure presented based on quantitative recoveries of Cr(III) > 95% using coprecipitation of Ni2+/2-Nitroso-1-naphthol-4-sulfonic acid. The total chromium was measured after reduction of Cr(VI) by concentrated H2SO4 and ethanol. The Cr(VI) was calculated as the difference between the total Cr content and the Cr(III) contents. The analytical variables, pH, amounts of precipitate, sample volume for optimum recoveries of Cr(III) were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries of analyte ions were also investigated. The preconcentration factor was 50. The detection limit (3σ) of the reagent blank for chromium(III) was 1.33 μg L−1. The relative standard deviations for determinations were found to be <7%, and % of relative error was calculated <6%. The method was validated by certified reference materials of tea (GBW 07605) and bush branches and leaves (GBW 0703). The procedure was successfully applied to the speciation of chromium in natural water and food samples (fish, white cheese, cow’s meat, black tea, boiled wheat).  相似文献   
67.

Introduction

This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents.

Methods

Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05.

Results

EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05).

Conclusions

The addition of surface modifiers to the irrigants did not affect the microhardness of the samples.  相似文献   
68.
Aim of the work: To evaluate the quality of life (QoL) in Familial Mediterranean Fever (FMF) patients, and determine its association with fatigue, depression, disease severity and other clinical parameters. Patients and methods: Sixty FMF patients were included. QoL was assessed by Short Form-36 (SF-36), depression by Hamilton Depression Scale (HDS), and fatigue by Fatigue severity scale (FSS). Disease severity score and Mutations of the Mediterranean fever (MEFV) gene were assessed. Results: The mean age of patients was 33.73 ± 9.81 years and disease duration 14.6 ± 12.1 years. They were 35 females and 25 males. FMF patients scored significantly higher in FSS (29.9 ± 17.6) and HDS (15.1 ± 8.5) compared to the control (10.6 ± 7.1 and 6.3 ± 9.4; p < 0.0001 respectively) while all SF36 sub-items except mental health were significantly lower (p < 0.05). MEFV gene mutation was present in 49 (81.7%) patients. The visual analogue scale of pain significantly negatively correlated with the FSS (p < 0.0001), HDS (p < 0.0001) and all SF36 sub-items except mental health (p < 0.0001). Disease duration, age of onset, and duration of attacks showed no significant correlation with FSS, HDS and SF36. Delay in diagnosis significantly correlated with FSS (p < 0.0001) and negatively with SF36 sub-items physical role (p = 0.02), general health (p = 0.01) and social functioning (p = 0.03). Age of diagnosis significantly correlated with FSS (p = 0.03) and negatively with SF36-vitality (p = 0.047). There was a significant effect of disease severity on QoL, fatigue and depression (p < 0.05). Conclusion: QoL is associated with fatigue, depression and disease severity in FMF patients. It should be used in routine clinical evaluation as an outcome measure in FMF.  相似文献   
69.
Purpose: Non-opioid medications as a part of multimodal analgesia has been increasingly suggested in the management of acute post-surgical pain. The present study was planned to compare the efficacy of the combination of pregabalin plus ?v ibuprofen. Methods: 58 patients were included in this prospective, randomized, double-blinded study. The pregabalin group (Group P, n = 29) received 150 mg pregabalin, the pregabalin plus ibuprofen group (Gropu PI, n = 29) received 150 mg pregabalin and 400mg ?v ibuprofen before surgery. Postoperative fentanyl consumption, additional analgesia requirements and PACU stay were recorded. Postoperative analgesia was performed with patient-controlled IV fentanyl. Results: VAS scores in the group PI were statistically lower at PACU, 1and 2 hours at rest, at PACU, 1, 2, 4, 12 and 24 hours on movement compared to the group P (P < 0.05). Opioid consumption was statistically significantly higher in the group P compared to the group PI (130.17 ± 60.27 vs 78.45 ± 60.40 μq, respectively, P < 0.001) and reduced in the 4th 24 hours by 55% in group PI. Rescue analgesia usage was statistically significantly higher in the group P than in the group PI (16/29 vs 7/29, respectively, P < 0.001). Four patient in the group PI did not need any opioid drug. Besides, PACU stay was shorter in the group PI than the group P (10.62 ± 2.38 vs 15.59 ± 2.11 min, respectively, P < 0.001). Conclusion: Preemptive pregabalin plus ?v ibuprofen in laparoscopic cholecystectomy reduced postoperative opioid consumption. This multimodal analgesic aproach generated lower pain scores in the postoperative period.  相似文献   
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号